Marine fisheries have been estimated to support the livelihoods of 10 to 12 percent of the world’s population and generate an average of $100 billion in revenue every year. But global fisheries are facing a number of challenges: changes in markets, demographics, and over-exploitation will significantly impact global fisheries in the near future, while climate change is expected to pose a major challenge over the longer term.

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A study published last month in the journal Scientific Reports explores the potential economic impacts of climate change as it affects the amount and composition of fish in marine fisheries and leads to decreased catches. Previous research has shown that global warming will cause changes in ocean temperatures, sea ice extent, salinity, and oxygen levels, among other impacts, that are likely to lead to significant shifts in the distribution range and productivity of marine species, the study notes.

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“Warmer temperatures may also lead to decreases in maximum body sizes of marine fishes,” write the authors of the study, a team of scientists from the University of British Columbia. These changes will be regionally specific, as predicted species distributional shifts and changes in ocean productivity due to climate change are expected to result in increases in maximum catch potential in high latitudinal regions but decreases in the tropics. The researchers add that “These changes have large implications for people who depend on fish for food and income, and thus the contribution of fisheries to the global economy.”

In all, the UBC researchers found that global fisheries could lose approximately $10 billion in annual revenue by 2050 if climate change continues unchecked — a 10 percent decrease, which is 35 percent more than has been previously estimated.

Previous research has shown that global warming will cause changes in ocean temperatures, sea ice extent, salinity, and oxygen levels, among other impacts, that are likely to lead to shifts in the range and productivity of marine species.

Countries that are most dependent on fisheries to feed their populations will experience the biggest impacts, according to the study. The largest average decrease in maximum catch potential will occur in small island countries like Tuvalu, which is expected to see a 79 percent drop in annual catches in its waters, and Kiribati, which is projected to see a 70 percent decrease.

“Developing countries most dependent on fisheries for food and revenue will be hardest hit,” Vicky Lam, a postdoctoral fellow at UBC’s Institute for the Oceans and Fisheries and the study’s lead author, said in a statement. “It is necessary to implement better marine resource management plans to increase stock resilience to climate change.”

On the other hand, some developed countries, such as Greenland and Iceland, could see revenue increases as fish move into cooler waters.

Lam and team used climate models from the Intergovernmental Panel on Climate Change to examine the economic impacts of climate change on fish stocks and fisheries revenues under two different emissions scenarios: a high-emission scenario, in which the rates at which greenhouse gases are pumped into the Earth’s atmosphere continue to rise unchecked, and a low-emission scenario under which ocean warming is kept below two degrees Celsius.

“Our modeling shows that a high emissions scenario could reduce global fishing revenue by an average of 10 percent, while a low emissions scenario could reduce revenues by 7 percent,” said study co-author Rashid Sumaila, a professor at UBC’s Institute for the Oceans and Fisheries and Liu Institute for Global Studies.

Many communities are considering aquaculture, or fish farming, as a means of easing the financial burden of fishing losses and improving food security as global temperatures continue to rise. But the UBC researchers examined the growing aquaculture industry and found it may actually exacerbate the negative impact on revenues.

“Climate adaptation programs such as aquaculture development may be seen as a solution,” said William Cheung, associate professor at UBC’s Institute for the Oceans and Fisheries and a co-author of the study. “However, rather than easing the financial burden of fishing losses and improving food security, it may drive down the price of seafood, leading to further decreases in fisheries revenues.”

Further research is needed to assess the full economic effects of various greenhouse gas emissions mitigation scenarios, the UBC researchers say. “Our results suggest the need to conduct full-fledged economic analyses of the potential economic effects of climate change on global marine fisheries,” they write.

This story originally appeared at the website of global conservation news service Mongabay.com. Get updates on their stories delivered to your inbox, or follow @Mongabay on Facebook, Instagram, or Twitter.

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